1. Field of the Invention
The invention relates to an output shaft locking device and a lock method for a multi-clutch transmission in which a plurality of rotational mechanisms, each of which is formed by arranging a clutch and a shifting mechanism in series, is provided in parallel between a rotational power input shaft and a rotational power output shaft.
2. Description of the Related Art
When parking a vehicle which has a parallel shaft type gear transmission by locking shifting gears, an output shaft of the transmission cannot be locked if a torque converter is provided between a clutch and an engine. Accordingly, a mechanism is known in which a lock gear that is to be engaged with a reverse idle gear is specially provided. In the mechanism, the reverse idle gear is engaged with the lock gear during parking such that an output shaft of a transmission is locked (refer to patent document 1). There is also a mechanism in which an output shaft of a transmission is locked by engaging an engaging member that is specially provided for a shifting gear (refer to patent documents 2 to 4). Further, a mechanism is known in which an input shaft of a transmission is directly locked by a specially provided parking lock mechanism (refer to patent document 5).
There is another type of known mechanism in which a rotational shaft of a transmission is locked by performing double engagement of shifting gears using a select lever, instead of employing the aforementioned specially provided lock mechanism (refer to patent document 6).
[Patent Document 1]
Japanese Patent Laid-Open Publication No. 2001-50392 (FIG. 2, pages 3-4)
[Patent Document 2]
Japanese Patent Laid-Open Publication No. 7-145862 (FIG. 2, pages 3-4)
[Patent Document 3]
Japanese Patent Laid-Open Publication No. 2001-280495 (FIG. 2, pages 4-5)
[Patent Document 4]
Japanese Utility Model Patent Laid-Open Publication No. 2-123454 (FIG. 2, page 1)
[Patent Document 5]
Japanese Patent Laid-Open Publication No. 2000-264178 (FIGS. 1-4, pages 3-6)
[Patent Document 6]
Japanese Patent Laid-Open Publication No. 2000-74214 (FIG. 1 pages 4-5)
When the aforementioned lock mechanism is applied to a twin clutch type transmission in which a plurality of, e.g., two rotational mechanisms, each of which is formed by arranging a clutch and a shifting mechanism in series, is provided in parallel between a rotational power input shaft and a rotational power output shaft, the following problems may occur.
When a structure provided with a lock mechanism is applied to the twin clutch type transmission as mentioned in patent documents 1 to 5, it becomes necessary to further provide a special lock mechanism to the transmission, which is itself already complex. This makes the arrangement of components difficult and increases the weight as well as costs.
In order to solve these problems, it is conceivable that the lock mechanism disclosed in the patent document 6 be applied to the twin clutch type transmission. However, unlike the transmission disclosed in the patent document 6, the twin clutch type transmission includes two clutches and two input shafts therein. Accordingly, it is still unclear how to select a shift for the double engagement, and how to control engagement/disengagement of the two clutches appropriately.